Format of config data in EPCS?

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originally posted by slacker@Aug 8 2006, 02:41 PM

andrew,

if i were you, i'd take a look at the algorithm used in:

$sopc_kit_nios2/components/altera_nios2/sdk/src/boot_loader_sources/boot_loader_epcs_bits.s.

yeah...it's assembly, but that might be what you want for a bootloader anyway, and it is pretty well commented...

cheers,

- slacker

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Thanks, that&#39;s what I needed. Just got done looking at that and I remember looking at it before for different reasons a while back. It is indeed well documented and easy to follow.

There&#39;s still some weirdness I don&#39;t understand related to the length of the bits but I think I&#39;ll be able to figure it out from here.

After giving it a little thought I realize that stashing the old EPCS program isn&#39;t that useful since there&#39;s not much I can do after programming the new version. After the next reboot I&#39;ll either have a working config or not and the backed-up version of the EPCS content won&#39;t do me any good.

I think eventually I&#39;ll write a two-stage bootloader where the first portion loads a known-good FPGA config with a minimal rescue monitor. That thing then can load the "real" FPGA config via a variety of methods, including EPCS or USB, which we have in our device using a FTDI chip.

Thanks again,

Andrew